1. Field of Invention
The present invention pertains to safety valves used in wells, and particularly to subsurface safety valves used in injection wells or storage facilities related to hydrocarbon production and processing operations.
2. Related Art
Subsurface safety valves are used in wells to prevent the uncontrolled flow of well fluids to the surface. A typical surface controlled subsurface safety valve has a hydraulic control line that supplies hydraulic pressure to the safety valve. So long as an appropriate level of hydraulic pressure is applied, the valve is held in its open state, allowing flow of fluids through the valve. When the pressure is removed or reduced below the required level, the valve moves to its default closed state, preventing flow of fluids through the valve.
Injection wells are typically used to improve production flow in neighboring wells, for storage of hydrocarbons, or for disposal of unwanted byproducts of hydrocarbon production activities (e.g., salt water). By injecting fluids such as water, for example, formation fluids may be displaced into neighboring wellbores so those formation fluids can be recovered. Injection wells may also be used to inject gas or chemicals. It is often desirable to include a safety valve in an injection well to prevent undesired production of fluids when no injection is being performed.